The present invention relates to a cigarette making machine including a system and method for assuring that bands formed on cigarette paper have proper width and spacing, and for rejecting cigarettes made from cigarette paper having out-of-tolerance band widths and spacings.
To ensure a high quality product, many manufacturers install optical inspection systems at various stages in the production line of an article of manufacture. Typically, each inspection station will include a source of electromagnetic radiation which directs the radiation toward the surface of the article of manufacture where it creates reflections. One or more sensors receive the reflections. Analysis of the received reflections provides insight into the characteristics of the article of manufacture, and in particular, whether the article may be irregular.
Prior art sensors of the type described above are typically designed and calibrated to detect specific articles. As such, these sensors can not easily be adapted to perform similar analysis on different articles. If the article changes, the manufacturer will be forced to redesign the sensor for compatibility with the new article. For instance, an engineer or technician might have to replace one or more circuit components associated with the sensor to calibrate the gain of the sensor's circuitry to accommodate different articles with varying reflectance properties.
Moreover, prior art optical inspection systems are primarily directed to ascertaining the presence of localized point anomalies, such as pinholes, tears and blemishes in a web of material. U.S. Pat. No. 5,426,509 to Peplinkski exemplifies this technique. In this system, the presence of an anomaly in a moving web causes a "spike" in the output of a sensor, which may be visualized using an oscilloscope. However, other anomalies are characterized by irregularities in the spatial relationship between elements or portions of the article of manufacture. An isolated analysis of a single point on an article, as described above, will not reveal these anomalies.
By way of illustration, consider the manufacture of banded cigarettes, one of which is illustrated in FIG. 1. As shown there, the cigarette 7 contains two bands 5 of material formed by depositing a layer of cellulosic pulp on base cigarette paper 3. Cellulon, microcrystalline cellulose, or amylopectin are various substances which have been used to form the bands. In order to provide a high quality product, it is desirable to ensure that the paper used to manufacture these cigarettes contains bands 5 having the proper width. Moreover, it is necessary to ensure that the spacing between adjacent bands is within tolerance. As illustrated in FIG. 2, cigarette paper 3 contains bands having proper widths (e.g. bands B.sub.1 -B.sub.5), and at least one band having an out-of-tolerance width (e.g. band B.sub.6). Also, the cigarette paper contains at least two adjacent bands having a spacing which is out-of-tolerance (e.g. the spacing between bands B.sub.4 and B.sub.5). The above described prior art optical inspection systems do not have the capability of detecting these anomalies.
Accordingly, it is an objective of the present invention to provide a system and method for analysis of a web of material, which does not suffer from the above noted drawbacks. It is another exemplary objective of the present invention to provide a sensor which can detect anomalies on different types of web materials without requiring a burdensome redesign or recalibration of the sensor. It is another exemplary objective of the present invention to provide an optical inspection system which ascertains whether paper containing bands includes bands having out-of-tolerance band widths, or out-of-tolerance spacings between adjacent bands.
It is a more specific objective of the present invention to provide a system and method for inspecting cigarette paper containing bands in a cigarette making machine and for rejecting cigarettes made from irregular sections of the cigarette paper.